Load supporting structure of electric booster type brake apparatus

Abstract

A load supporting structure of an electric booster type brake apparatus, includes: a housing including a rear housing member and a front housing member so as to define a receiving space therein; a ball screw shaft rotatably installed in the receiving space of the housing; a rotor installed at one side of the ball screw shaft so as to transmit torque; a first bearing installed between the rear housing member and one side of the rotor and configured to support a radial direction load due to a hydraulic reaction force; and a second bearing installed between the front housing member and the other side of the rotor and configured to support an axial direction load due to a hydraulic reaction force. Therefore, the number of components and the thickness of the housing are reduced, and therefore weight reduction of the electric booster type brake apparatus may be implemented.

What is claimed is: 
     
       1. A booster apparatus for a vehicle brake system, the apparatus comprising:
 a housing comprising a rear housing member and a front housing member that define a receiving space therein; 
 a ball screw shaft at least in part installed in the receiving space of the housing and rotatable about an axial direction; 
 a rotor rotatable about the rotational axis and connected to the ball screw shaft for transferring torque of the rotor to the ball screw shaft; 
 the rotor comprising a sleeve extending in the axial direction and a flange extending in the radial direction; 
 a first bearing installed between the rear housing member and the rotor, wherein the first bearing abuts the sleeve such that a radial direction load applied to the rotor is transferred to the rear housing member via the first bearing; and 
 a second bearing installed between the front housing member and the rotor, wherein the second bearing abuts the flange such that an axial direction load applied to the rotor is transferred to the front housing member via the second bearing. 
 
     
     
       2. The apparatus of  claim 1 , wherein the front housing member comprises an axial load supporting portion that abuts the second bearing. 
     
     
       3. The apparatus of  claim 2 , wherein the first bearing has a diameter smaller than that of the second bearing. 
     
     
       4. A vehicle comprising the booster of  claim 1 .